JP7051365B2 - Image processing equipment, image processing methods, and programs - Google Patents

Description

The present invention relates to a technique for processing an omnidirectional image captured and acquired.

In recent years, in a surveillance camera, which is one of image pickup devices, there is an omnidirectional camera (for example, a surveillance camera equipped with a lens having a horizontal and vertical angle of view of 180 degrees or more) that can monitor and shoot a wide range from a bird's-eye view. In the case of an omnidirectional camera, a part of the outer edge of the image circle is included inside the image pickup range of the image sensor, so that the image output from the image sensor of the omnidirectional camera is the area of the image circle on which the light is incident. The image is an image in which the boundary of the region without light incident exists.

In addition, color bleeding, so-called fringe, may be visually recognized in an image captured by a digital still camera including a surveillance camera, a digital video camera, or the like. Fringe refers to a phenomenon in which when a contour with a large difference in luminance is present in a captured image, color bleeding such as a blue or purple border occurs in the contour portion. In the case of an image having a boundary between a region having light incident and a region without light incident due to an image circle, such as an image captured by the above-mentioned omnidirectional camera, fringes are particularly likely to occur.

The generation of fringes is caused by processes such as an image sensor, a lens, and image processing, and various methods for solving this problem have been conventionally proposed. For example, Patent Document 1 discloses a method in which the characteristics of a lens are measured in advance, correction data is stored in a memory, and correction processing is executed using the correction data at the time of shooting. Further, Patent Document 2 discloses a method of performing fringe correction by performing a plurality of shootings to acquire a plurality of images having different shooting conditions and synthesizing the images.

Japanese Patent Application Laid-Open No. 2003-60983 Japanese Unexamined Patent Publication No. 2011-21129

However, in the method of measuring the characteristics of the lens in advance and storing the color bleeding correction data in the memory as in the method of Patent Document 1, the memory capacity increases, the adjustment process increases, the configuration becomes complicated, and the lens becomes more complicated. It is difficult to accurately correct all the effects related to. Further, in the technique of Patent Document 2, it is not necessary to store the color blur correction data in advance, but it is necessary to perform photography twice or more, which increases the processing amount.

Therefore, an object of the present invention is to make it possible to suppress color bleeding of a captured image with a simple configuration and a small amount of processing.

The present invention is based on an acquisition means for acquiring a saturation parameter for determining the saturation in an image circle of an omnidirectional image captured, the saturation parameter , and the position of a pixel in the image circle . , The calculation means for calculating the saturation level correction parameter for determining the intensity for reducing the saturation by the saturation level correction processing, and the saturation of the captured omnidirectional image, the saturation level correction parameter. The calculation means includes a processing means for performing a saturation level correction process for reducing the saturation according to the above, and the calculation means lowers the saturation of the pixel on the outer edge side in the image circle than on the center side of the image circle. It is characterized in that the saturation level correction parameter is calculated so as to be performed.

According to the present invention, it is possible to suppress color bleeding of a captured image with a simple configuration and a small amount of processing.

It is a figure which shows the schematic configuration example of the image pickup system of this embodiment. It is a figure which shows the schematic internal structure example of the image pickup apparatus of this embodiment. It is a block diagram which shows the structural example of an image processing part. It is a block diagram which shows the structural example of the development processing part. It is a block diagram which shows the structure of the saturation level correction processing part example. It is a flowchart of the saturation level correction parameter calculation of 1st Embodiment. It is a figure which shows the relationship of the image pickup element, the image circle, and the pixel corresponding to the saturation level correction processing. It is a figure which shows the relationship between the saturation level correction parameter and the image height position. It is a figure which shows the saturation level correction parameter and a plurality of change points of an image height position. It is a flowchart of the saturation level correction parameter calculation of 2nd Embodiment. It is explanatory drawing of the saturation level correction which added the color component of 2nd Embodiment. It is a figure which showed the example which generates the panoramic image from the omnidirectional image. It is a flowchart of the saturation level correction parameter calculation of 3rd Embodiment. It is explanatory drawing of the saturation level correction which added the display mode of 3rd Embodiment.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an imaging system according to the present embodiment.
The image pickup system shown in FIG. 1 is a client device connected to a surveillance camera 101 as an image processing device for capturing a moving image and performing image processing according to the present embodiment in a state in which they can communicate with each other via an IP network. It is configured to have 102. It is assumed that the client device 102 includes, for example, a personal computer and a display device. In the present embodiment, an example in which the surveillance camera 101 has a function of an image processing device will be described, but it is also possible for the client device 102 to perform image processing according to the present embodiment. Further, in the present embodiment, the surveillance camera 101 is assumed to be, for example, an omnidirectional camera (surveillance camera equipped with a lens having a horizontal and vertical angle of view of 180 degrees or more) capable of monitoring and photographing a wide range from a bird's-eye view. ..

FIG. 2 is a diagram showing a schematic internal configuration example of the surveillance camera 101 of the present embodiment.
The image pickup optical system 201 includes a zoom lens, a focus lens, a blur correction lens, a diaphragm, a shutter, and the like, collects light from the subject and the like, and captures an optical image of the subject and the like as an image pickup element of the image pickup sensor 202. It is formed on the image pickup surface (sensor surface) of. In the case of the present embodiment, it is assumed that the lens of the imaging optical system 201 is a lens having a horizontal and vertical angle of view of 180 degrees or more. The image pickup sensor 202 has an image pickup element that converts an optical image formed on the image pickup surface by the image pickup optical system 201 into a current value. The image pickup sensor 202 also acquires RGB color information by providing a color filter on the image pickup surface of the image pickup element. Further, it is assumed that the image sensor 202 can set an arbitrary exposure time for all the pixels of the image sensor.

The CPU 203 is involved in all the processing and control of each configuration, sequentially reads and interprets the instructions stored in the ROM (read-only memory) 204 and the RAM (random access memory) 205, and each processing and control according to the result. To execute. Under the instruction from the CPU 203, the image pickup system control unit 206 performs various image pickup controls such as a control for focusing on the image pickup optical system 201, a control for opening and closing a shutter, and a control for adjusting an aperture. The control unit 207 performs control according to an instruction from the client device 102. The A / D conversion unit 208 converts the image pickup signal from the image pickup sensor 202 into image data of digital signal values. The image processing unit 209 is a unit that performs image processing according to the present embodiment on the image data from the A / D conversion unit 208, and the details thereof will be described later. The encoder unit 210 converts (encodes) the image data after the image processing by the image processing unit 209 into a file format such as so-called Motion Jpeg or H264. The image data after the encoding process by the encoder unit 210 is output to, for example, the client device 102.

FIG. 3 is a block diagram showing a schematic internal configuration of the image processing unit 209 of the present embodiment.
The image input unit 301 acquires image data imaged by the image sensor 202 described above and digitally converted by the A / D conversion unit 208. The preprocessing unit 302 performs correction processing such as removal of fixed pattern noise caused by the image pickup sensor and gain adjustment. The development processing unit 303 performs development processing on the image data after the correction processing by the preprocessing unit 302. The post-processing unit 304 applies a spatial NR filter and a temporal NR filter to the image developed by the development processing unit 303 to reduce randomly generated noise. The image output unit 305 outputs the image data from the post-processing unit 304 to the encoder unit 210 in FIG.

FIG. 4 is a block diagram showing an example of the internal configuration of the development processing unit 303.
The development processing unit 303 includes a demosaic processing unit 401, a white balance processing unit 402, a saturation level correction processing unit 403, and a gamma processing unit 404. The demosaic processing unit 401 performs demosaic processing on the image data input from the preprocessing unit 302, and the white balance processing unit 402 performs white balance processing on the image data after the demosaic processing. The details of the saturation level correction processing unit 403 will be described later, but the color bleeding can be made inconspicuous by performing the saturation difference level correction processing by the saturation level correction processing unit 403. The gamma processing unit 404 performs gamma processing on the image data input from the saturation level correction processing unit 403. Then, the image data output from the gamma processing unit 404 is sent to the post-processing unit 304 of FIG.

<Saturation level correction processing of the first embodiment>
Hereinafter, the configuration of the saturation level correction processing unit 403 and the saturation level correction processing in the first embodiment will be described.
FIG. 5 is a block diagram showing a schematic configuration example of the saturation level correction processing unit 403 according to the first embodiment. It is assumed that the saturation level correction processing unit 403 of the first embodiment is configured to perform saturation level correction for the image of each frame of the moving image signal. The saturation level correction processing unit 403 includes an input signal acquisition unit 501, a saturation enhancement processing parameter acquisition unit 502, a saturation level correction parameter calculation processing unit 503, and a saturation level correction execution processing unit 504.

FIG. 6 is a flowchart showing the flow of the saturation level correction processing executed by the saturation level correction processing unit 403 of the first embodiment. Hereinafter, the flow of the saturation level correction process in the first embodiment will be described with reference to the flowchart of FIG. In the following description, each processing step S601 to S604 in the flowchart of FIG. 6 will be abbreviated as S601 to S604. The processing of the flowchart of FIG. 6 may be executed by the hardware configuration, or may be partially realized by the software configuration and the rest by the hardware configuration. When the processing is executed by the software configuration, it is realized by, for example, the CPU or the like executing the image processing program according to the present embodiment stored in the ROM. The program according to the present embodiment may be prepared in advance in the ROM, may be read from a detachable semiconductor memory or the like, or may be downloaded from a network such as the Internet (not shown). It is assumed that these things are the same in other flowcharts described later.

First, in S601, the input signal acquisition unit 501 acquires an image (hereinafter referred to as an omnidirectional image) for each frame of the moving image signal captured by the surveillance camera 101 of the present embodiment, which is an omnidirectional camera.
Next, in S602, the saturation enhancement processing parameter acquisition unit 502 includes a saturation parameter (hereinafter referred to as a saturation enhancement processing parameter) that determines how much the saturation (color density) is emphasized with respect to the input image. To). For example, in the case of a surveillance camera, the user can adjust how much the saturation is emphasized by inputting an instruction via the client device 102. Hereinafter, the process of adjusting the saturation is referred to as the saturation level correction process. More specifically, when the adjustment range of the saturation level correction process that can be selected by the user is, for example, in the range of "0 to 100" and the user specifies the saturation level correction process with an intensity of "50", the saturation The enhancement processing parameter acquisition unit 502 acquires a "50" value as the saturation enhancement processing parameter. The "50" value as the saturation enhancement processing parameter is a standard value, and is assumed to be the same value as the saturation level set by default when not specified by the user.

Next, in S603, the saturation level correction parameter calculation processing unit 503 calculates the saturation level correction parameter based on the saturation enhancement processing parameter and the position of the pixel in the captured image. In the present embodiment, the positions of the pixels in the captured image when calculating the saturation level correction parameter are acquired as the image height representing the distance from the center of the image pickup surface of the image pickup device or the coordinate position. If the center of the image circle can be accurately specified, the distance from the center of the image circle may be acquired as the position of the pixel.
After that, in S604, the saturation level correction execution processing unit 504 executes the saturation level correction processing according to the saturation level correction parameter calculated in S603 for the captured image acquired by the input signal acquisition unit 501. ..

Hereinafter, the calculation process of the saturation level correction parameter of S603 described above will be described more specifically by using FIGS. 7 to 9 and the following equations (1) and (2).
FIG. 7 is a diagram schematically showing an image pickup range 700 of an image pickup element included in the image pickup sensor 202 and an image circle 701 formed by the image pickup optical system 201. Here, in FIG. 7, the coordinate position of the corresponding pixel 702 on which the saturation level correction processing is executed is (x, y), and the coordinate position of the center of the image pickup surface of the image pickup device (hereinafter referred to as the screen center 703). (X, Y), and the distance from the center of the image circle 701 to the outer edge is represented as R. It is assumed that the center of the screen 703 and the center of the image circle 701 are the same. At this time, the image height index M (x, y) indicating how far the corresponding pixel 702 is from the screen center 703 is calculated by the following equation (1).
M (x, y) = {(X-x) ² + (Y-y) ² } / R ² equation (1)

Here, when the image height index M (x, y) takes a value of, for example, 0.0 to 1.0, it is assumed that the corresponding pixel 702 represents a pixel included in the image circle 701. On the other hand, when the image height index M (x, y) takes a value larger than, for example, 1.0, it is assumed that the corresponding pixel 702 represents a pixel existing outside the image circle 701.
Further, it is assumed that the saturation level correction parameter for the corresponding pixel 702 at the coordinate position (x, y) is expressed as the correction parameter N (x, y). Here, for example, it is assumed that the adjustment range of the saturation level correction processing is in the range of "0 to 100" and the saturation enhancement processing parameter acquired in S602 is "50". In this case, the correction parameter N (x, y) uses the image height index M (x, y) indicating how far away from the screen center 703 calculated by the equation (1), and the following equation (2) is used. Can be calculated by

FIG. 8 is a diagram showing an example of the relationship between the image height index M (x, y) represented by the equation (2) and the correction parameter N (x, y) by the solid line 800. The vertical axis of FIG. 8 represents the correction parameter N, and the horizontal axis represents the image height index M. As shown by the solid line 800 in FIG. 8, the correction parameter N (x, y) is set to a value that reduces the saturation level as it is closer to the outer edge of the image circle. Since there is a high possibility that the central part of the image circle is photographed, for example, the user's monitoring target, etc., in FIG. 8, the relationship is such that the intensity of the saturation level correction processing matches the saturation enhancement processing parameter intended by the user. It has been done. That is, in the case of the example of FIG. 8, the correction parameter N (x, y) is set to a value closer to the saturation enhancement processing parameter “50” as it approaches the center of the image circle. As a result, when the saturation level correction process using this correction parameter N (x, y) is executed by the saturation level correction execution processing unit 504, the saturation level becomes smaller as it is closer to the outer edge of the image circle. .. Therefore, at the outer edge, the saturation level is smaller than before applying the saturation level processing, and the color of the fringe is changed from blue or purple to achromatic color, and it is possible to suppress (make it inconspicuous) color bleeding. Will be. On the other hand, in FIG. 8, the correction parameter N such that the saturation level becomes 0 in S604 for the region without light incident (the region where the image height index M is larger than 1.0) located outside the image circle. (X, y) is set. Alternatively, in the saturation level correction execution processing unit 504, the saturation level correction processing is executed only for the region where the light is incident on the image sensor, and the saturation level correction processing is not executed for the region where the light is not incident. You may do so.

The correction parameter N is not limited to the values calculated by the equations (1) and (2). For example, as shown by the solid line 900 in FIG. 9, the correction parameter N can be set by providing a plurality of change points 901. A method of smoothly calculating the change may be adopted. In FIG. 9, similarly to FIG. 8, the vertical axis represents the correction parameter N and the horizontal axis represents the image height index M. Further, the correction parameter N is not limited to the intensity of the saturation level correction processing, and a correction parameter such as a gain for a color component may be adopted.

In the first embodiment, by setting the correction parameter N as described above, it becomes possible to suppress the fringe generated at the outer edge of the image circle while realizing the saturation intended by the user in the central portion. .. That is, in the saturation level correction processing unit 403 of the present embodiment, the processing of S601 to S604 of FIG. 6 described above is performed on the image data of the moving image, so that the input image has a simple configuration and a small amount of processing. It is possible to suppress the occurrence of color bleeding.
In the first embodiment, the saturation level correction process is executed in the surveillance camera 101, but the target to which the saturation level correction process is executed is not particularly limited. For example, when using a fisheye lens, when using a wide-angle lens such that a part of the outer edge of the image circle is included inside the image pickup range of the image sensor, or when vignetting occurs at the four corners of the image. It is possible to execute the same process.

<Saturation level correction processing of the second embodiment>
In the first embodiment described above, in S603 of FIG. 6, the saturation level correction parameter calculation processing unit 503 sets the saturation level correction processing parameter according to the saturation enhancement processing parameter and the pixel position (image height or coordinates). The calculation method was explained. In the following second embodiment, the saturation level correction parameter calculation processing unit 503 calculates the saturation level correction parameter in consideration of the color component information in addition to the saturation enhancement processing parameter and the pixel position. In the second embodiment, the configuration related to the image processing is the same as that of the first embodiment described above, so the illustration and description thereof will be omitted. Also in the second embodiment, the same reference numerals are given to the same configurations as those in the first embodiment, and the description thereof will be omitted.

FIG. 10 is a flowchart of the parameter calculation process of the saturation level correction process in the saturation level correction parameter calculation process unit 503 of the second embodiment. Hereinafter, the flow of the saturation level correction process of the second embodiment will be described with reference to the flowchart of FIG.
First, in S1001, the saturation level correction parameter calculation processing unit 503 uses the RGB value of the input signal as the luminance (Y) component and the color (UV) in order to acquire the color component, as shown in the following equation (3). ) Convert to components.

Y (x, y) = 0.299 x R (x, y) + 0.587 x G (x, y) + 0.114 x B (x, y)
U (x, y) = -0.169 x R (x, y) -0.331 x G (x, y) + 0.500 x B (x, y) Equation (3)
V (x, y) = 0.500 x R (x, y) -0.419 x G (x, y) -0.081 x B (x, y)

Here, R (x, y), G (x, y), and B (x, y) in the equation (3) represent RGB signal values at the coordinate position (x, y), and Y (x, y) ,. U (x, y) and V (x, y) represent YUV signals. The color signal is not limited to the value calculated by the equation (3), and the a and b values obtained by the Lab conversion and the Cb and Cr values obtained by the YCbCr conversion may be adopted.

Subsequently, in S1002, the saturation level correction parameter calculation processing unit 503 acquires the magnitude of the UV component for each image height from the outer edge of the image circle to the center of the screen, and the acquired value is 0.0 to 1.0. Normalize to a value. Hereinafter, the value obtained by normalizing the magnitude of the UV component is referred to as UV intensity O (x, y).
Further, in step S1003, the saturation level correction parameter calculation processing unit 503 uses the image height index M (x, y) according to the equation (1), the saturation enhancement processing parameters L, and the UV intensity O (x, y) according to S1002. , The correction parameter N (x, y) is calculated by the equation (4).

11 (a) and 11 (b) are diagrams used for explaining the relationship between the UV intensity O, the image height index M, and the correction parameter N when the correction parameter N is calculated using the equation (4). FIG. 11A is a diagram showing an image pickup range 1100 and an image circle 1101 of the image pickup device. As shown in FIG. 11A, in the image circle 1101, the region C1 on the center side of the screen has many subjects with high UV components (regions with high UV intensity), and the region C2 at the intermediate position is an almost achromatic subject. It is assumed that there are many distributions (regions with low UV intensity). On the other hand, the region C3 of the outer edge portion of the image circle 1101 is a region in which a relatively large number of subjects having a high UV component are distributed. FIG. 11B is a diagram showing an example of the relationship between the image height index M and the correction parameter N in the second embodiment by a solid line 111, and the vertical axis is the correction parameter N, as in FIG. 8 described above. The horizontal axis represents the image height index M.

As shown in FIGS. 11 (a) and 11 (b), for a region containing a large amount of color components (large UV component) such as region C1 and region C3, the color is colored by the saturation level correction parameter. The change in the intensity of the degree level correction process is made gradual. For example, in the region C1 in which a large amount of UV components are distributed (high UV intensity) in the center of the screen, the change in the saturation level correction parameter is substantially eliminated to make the change in saturation smaller. Further, in the region C3 where a relatively large amount of UV components are distributed on the outer edge of the image circle, the change in the saturation level correction parameter is made small so that a step in saturation does not occur. On the other hand, for the region C2 that is close to achromatic color such as the intermediate position, the saturation level correction parameter is greatly changed to increase the change in saturation.

As described above, according to the second embodiment, by calculating the saturation level correction processing parameter in consideration of the UV intensity O (x, y), different saturation level correction processing is executed for each image height position. Even in this case, the difference in saturation for each image height can be made inconspicuous.
Further, the correction parameter N is not limited to the value calculated by the equation (4), and a method of calculating the correction parameter N may be adopted, for example, as in the equation (5).

When the saturation level correction parameter is calculated using the equation (5), even if the saturation level correction processing is executed for a subject having a large color component existing on the outer edge of the image circle, the saturation intended by the user is executed. Will be possible. It should be noted that a method of calculating by combining the calculation methods of the equation (4) and the equation (5) according to the image height position may be adopted.
As described above, according to the second embodiment, it is possible to suppress the color bleeding that occurs at the outer edge of the image circle while reducing the difference in saturation for each image height caused by the saturation level correction processing. ..

<Saturation level correction processing of the third embodiment>
In the third embodiment, an example in which the saturation level correction parameter calculation processing unit 503 calculates the saturation level correction parameter in consideration of the display mode in addition to the saturation enhancement processing parameter and the image height or coordinates of the pixel. explain. In the third embodiment, the configuration related to the image processing is the same as that of the first embodiment described above, so the illustration and description thereof will be omitted. Also in the third embodiment, the same reference numerals are given to the same configurations as those in the first embodiment, and the description thereof will be omitted.

Here, in the image pickup system of the present embodiment, the user can arbitrarily set the display method when displaying an image on the display device of the client device 102. As an example, the display method is set by the user specifying a desired display mode from a plurality of display modes. The display mode is, for example, a panoramic image after the user specifies an arbitrary area for an image taken by an omnidirectional camera and performs distortion correction on the distorted omnidirectional image. The mode to be displayed (referred to as panoramic mode) can be mentioned.

FIG. 12 is a diagram showing an image pickup range 1200 and an image circle 1201 of an image pickup device. The omnidirectional image of the image circle 1201 is divided into an area P1 displayed in the panoramic mode and an area P2 not displayed in the panoramic mode. When the display is performed in the panoramic mode, the image of the region P1 is taken out from the omnidirectional image of the image circle 1201, and after distortion correction, it is displayed as the panoramic image 1210. As shown in FIG. 12, for example, when the user wants to display a panoramic image, the panoramic image 1210 is created using the region P1 excluding the central portion of the omnidirectional image. Here, in the panorama mode, as shown in FIG. 12, since a part of the image circle 1201 is not displayed, there is an area in which the effect of the saturation level correction processing is not reflected in the image being monitored by the user, for example. It will be. That is, since there is an area in which the effect of the saturation level correction processing is not reflected in the image depending on the display mode, the saturation level correction parameter corresponding to the display mode is calculated in the saturation level correction parameter calculation processing of the third embodiment. do.

FIG. 13 is a flowchart of the saturation level correction parameter calculation process in the third embodiment. Hereinafter, the processing flow of the saturation level correction processing in the third embodiment will be described with reference to the flowchart of FIG.
First, in S1301, the saturation level correction parameter calculation processing unit 503 acquires the display mode selected by the user, for example, via the client device 102.
Subsequently, in step S1302, the saturation level correction parameter calculation processing unit 503 sets the image height index M (x, y) according to the equation (1), the saturation enhancement processing parameter L, and the display mode acquired in S1301. Based on this, the saturation level correction parameters are calculated.

14 (a) and 14 (b) explain the relationship between the image height index M and the saturation level correction parameter (correction parameter N) when the panorama mode is selected as the display mode in the third embodiment. It is a figure to use. FIG. 14A is a diagram showing an image pickup range 1400 and an image circle 1401 of an image pickup device. As shown in FIG. 14A, in the image circle 1401, the area P2 on the center side of the screen is an area that is not displayed in the panoramic mode, and the other area P1 is an area that is displayed in the panoramic mode. FIG. 14B is a diagram showing an example of the relationship between the image height index M and the correction parameter N in the case of the third embodiment by a solid line 1411, and the vertical axis is the correction parameter N, as in FIG. 8 described above. The horizontal axis represents the image height index M.

In the case of the third embodiment, as shown in FIGS. 14 (a) and 14 (b), the saturation level correction parameter is equivalent to the value obtained from the saturation enhancement processing parameter in the region P2 not displayed in the panorama mode. Set to a value. Further, in the area P1 displayed in the panoramic mode excluding the area P2 in the image circle 1401, the saturation level correction processing is performed according to the image height index M, as described with FIG. 8 of the first embodiment. The saturation level correction parameter is set so that the intensity gradually decreases.

As described above, in the third embodiment, by calculating the saturation level correction processing parameter according to the display mode, it is possible to execute the optimum saturation level correction processing according to the display mode selected by the user. become.
In the third embodiment, an example in which the information of the display mode is added to the saturation enhancement processing parameters and the pixel positions (image height or coordinates) described in the first embodiment is given, but further in the second embodiment. The saturation level correction processing parameter may be calculated by adding the information of the color component described.

As described above, in the first to third embodiments, a saturation level correction process suitable for an image in which a part of the outer edge of the image circle (imaging range) is included in the imaging range of the image pickup device is performed. Therefore, color bleeding can be suppressed. According to the first to third embodiments, in a surveillance camera capable of capturing an omnidirectional image, color bleeding that occurs in the captured image with a simple configuration and a small amount of processing, particularly fringes that occur in the outer edge region of the image circle. It becomes possible to realize the saturation level correction processing for suppressing the occurrence of.

<Other embodiments>
The image processing device of the present embodiment is not limited to the surveillance camera. For example, it can be applied to various mobile terminals such as digital cameras, digital video cameras, and smartphones and tablet terminals equipped with camera functions that can shoot a wide range of angles, as well as industrial cameras, in-vehicle cameras, and medical cameras. This embodiment is also applicable to the above.

The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The above-mentioned embodiments are merely examples of embodiment in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from its technical idea or its main features.

101: Surveillance lens, 101: Client device, 201: Imaging optical system, 202: Image sensor, 209: Image processing unit, 203: CPU, 403: Saturation level correction processing unit, 503: Saturation level correction parameter calculation processing unit , 504: Saturation level correction execution processing unit

Claims (9)

An acquisition means for acquiring the saturation parameters for determining the saturation in the image circle of the captured omnidirectional image, and
A calculation means for calculating the saturation level correction parameter for determining the intensity for reducing the saturation by the saturation level correction processing based on the saturation parameter and the position of the pixel in the image circle .
A processing means for performing a saturation level correction process for reducing the saturation of the captured omnidirectional image to a saturation corresponding to the saturation level correction parameter.
Equipped with
The calculation means is an image processing apparatus characterized in that the saturation level correction parameter is calculated so that the saturation of the pixel on the outer edge side in the image circle is lower than that on the center side of the image circle . The image processing apparatus according to claim 1, wherein the captured omnidirectional image is an image in which at least a part of the outer edge of the image circle is included in the image pickup range of the image pickup device. The image processing apparatus according to claim 1 or 2, wherein the calculation means uses image height or coordinates representing a distance from the center of the image pickup surface of the image pickup device as the position of the pixel. The image processing apparatus according to any one of claims 1 to 3 , wherein the calculation means calculates the saturation level correction parameter having a plurality of change points. The processing means executes the saturation level correction processing on the region where the light is incident on the image sensor, and does not execute the saturation level correction processing on the region where the light is not incident. The image processing apparatus according to any one of claims 1 to 4 , which is characterized. The calculation means is characterized in that the saturation level correction parameter is calculated based on the information of the saturation parameter , the position of a pixel in the image circle , and the color component of the captured omnidirectional image. The image processing apparatus according to any one of claims 1 to 5 . The calculation means calculates the saturation level correction parameter based on the saturation parameter , the position of the pixel in the image circle , and the information of the display method when the omnidirectional image is displayed. The image processing apparatus according to any one of claims 1 to 6 , which is characterized. It is an image processing method executed by an image processing device that processes an captured omnidirectional image.
The acquisition process for acquiring the saturation parameter for determining the saturation in the image circle of the captured omnidirectional image, and the acquisition process.
A calculation step of calculating the saturation level correction parameter for determining the intensity for reducing the saturation by the saturation level correction process based on the saturation parameter and the position of the pixel in the image circle .
A processing step of performing a saturation level correction process of reducing the saturation of the captured omnidirectional image to a saturation corresponding to the saturation level correction parameter, and
Equipped with
The calculation step is an image processing method characterized in that the saturation level correction parameter is calculated so that the saturation of the pixel on the outer edge side in the image circle is lower than that on the center side of the image circle . A program for operating a computer as the image processing device according to any one of claims 1 to 7 .

Images